/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.optimize;

import proguard.classfile.*;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.visitor.MemberVisitor;
import proguard.evaluation.value.Value;
import proguard.optimize.evaluation.StoringInvocationUnit;

/**
 * This <code>MemberVisitor</code> delegates its visits to program class members to another given
 * <code>MemberVisitor</code>, but only when the visited class member has been marked as a constant.
 *
 * @see StoringInvocationUnit
 * @author Eric Lafortune
 */
public class ConstantMemberFilter extends SimplifiedVisitor implements MemberVisitor {
    private final MemberVisitor constantMemberVisitor;

    /**
     * Creates a new ConstantMemberFilter.
     * 
     * @param constantMemberVisitor the <code>MemberVisitor</code> to which visits to constant members will be
     *        delegated.
     */
    public ConstantMemberFilter(MemberVisitor constantMemberVisitor) {
        this.constantMemberVisitor = constantMemberVisitor;
    }

    // Implementations for MemberVisitor.

    public void visitProgramField(ProgramClass programClass, ProgramField programField) {
        Value value = StoringInvocationUnit.getFieldValue(programField);
        if (value != null && value.isParticular()) {
            constantMemberVisitor.visitProgramField(programClass, programField);
        }
    }

    public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod) {
        Value value = StoringInvocationUnit.getMethodReturnValue(programMethod);
        if (value != null && value.isParticular()) {
            constantMemberVisitor.visitProgramMethod(programClass, programMethod);
        }
    }
}
